Microstructure and Fatigue Properties of Resistance Element Welded Joints of DP500 Steel and AW 5754 H22 Aluminum Alloy

Abstract

The modern concept of lightweight design (LW) requires the application of different materials in one structure (multi-material structures). The structure of different materials has a good perspective for application in the automotive and aerospace industries but only if it is possible to achieve a quality joint between different materials. The most used technology for joining different materials in the automotive industry is Resistance spot welding (RSW). Due to different mechanical, physical, and chemical properties, the joining of different materials by RSW technology does not provide a quality joint, and accordingly, alternative technologies for joining different materials have emerged. Resistance element welding (REW) was developed to enable joint of different materials. This paper presents the welding of AW 5754 H22 Al alloy (1.0 mm-thick) and DP500 steel (1.5 mm-thick) using novel REW. The peak load, absorption energy, microstructure, microhardness and fatigue strength of the REW joint has been investigated. The joint of the same materials has been done also using conventional RSW to compare some results. The results that will be presented in this paper show that that REW can achieve reliable joining of the two materials at relatively low welding currents compared to RSW. Using REW process with a significantly lower welding current, satisfactory mechanical characteristics of the weld joint can be achieved, so peak load is between 2300–2500 N, displacement is between 2.5–3 mm and the absorption energy is between 3.3–5.7 J. REW joints showed fatigue strength with the fatigue limit of 882 N.

Joining technology of steel and alluminum alloy sheets: State of the art

“…Osnovna prednost REW postupka je što u poređenju sa RSW postupkom se razlikuje samo za fazu ubacivanja elementa od čelika u aluminijum, što se može jednostavno automatizovati, tako da ovaj način spajanja ne zahtijeva velika dodatna ulaganja u postojeće fabrike za sklapanje automobila. S druge strane istraživanja koja su do sada obavljena pokazuju da REW spoj aluminijuma i čelika ima bolja integralna mehanička svojstva nego spoj ova dva materijala dobijen RSW tehnologijom spajanja [13,[22][23][24][25]. Takođe, životni vijek elektroda značajno je duži kod REW nego kod RSW tehnologije spajanja [25].…”

Effects of Interlayer on the Microstructure and Mechanical Properties of Resistance Spot Welded Titanium/Steel Joints: A Short Review

“…Resistance spot welding (RSW) technology is a method that uses the resistance heat generated by the current through the base material to heat the base material until the base material melts, forming solder joints after solidification to achieve metallurgical bonding [4][5][6]. A schematic diagram of the device is shown in Figure 1, and the main process parameters are current, energizing time and electrode pressure [7][8][9]. The welding process is divided into three successive stages.…”

Fatigue Behaviour of Brazed Joints for Heat Exchangers

“…In different engineering applications, different devices may be found to transfer heat from hot to cold water. One of them is a heat exchanger, which can be used for central heating of houses, heating of domestic water and many other purposes, including the provision for different kinds of industries, e.g., the food industry, the pharmaceutical industry, and others [1][2][3][4][5].…”